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An atomic-level insight into the mechanisms of heterogeneous catalytic reduction of carbon dioxide

An atomic-level insight into the mechanisms of heterogeneous catalytic reduction of carbon dioxide E . Vesselli Physics Dept. and CENMAT, Università degli Studi di Trieste (Italy ) and Laboratorio TASC IOM-CNR (Italy ) vesselli@iom.cnr.it. About the importance of

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An atomic-level insight into the mechanisms of heterogeneous catalytic reduction of carbon dioxide

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  1. An atomic-level insight into the mechanisms of heterogeneous catalytic reduction of carbon dioxide E. Vesselli Physics Dept. and CENMAT, UniversitàdegliStudi di Trieste (Italy) and LaboratorioTASC IOM-CNR (Italy) vesselli@iom.cnr.it

  2. About the importance of CO and CO2 catalytic reduction in Nature

  3. Catalysis in Nature the origin of life? Comets Ice (water) + Fe, Ni, silicates … Bricks for life? Catalytic CO2 reduction J. Llorca, Intern. Microbiol. 8(2005 ) 5

  4. CO2 Catalysis in NATURE Photosynthesis: catalytic carbon dioxide reduction == chemical energy for life Acetogenicbacteria Carbon fixation pathway to convert CO/CO2 to acetyl groups Ni-Fe-Cu reaction center Carbon fixation reaction (PS-II): 3CO2 + 9ATP + 6NADPH + 6H+ → C3H6O3-phosph + 9ADP + 8Pi + 6NADP+ + 3H2O PS-II: Mn4Ca2+O4 cluster A 9 atom cluster does the catalysis job! -> 2.5 billion years old NANOTECHNOLOGY Doukov, et al.Science. 298(2002) 567 K.N. Ferreira, et al. Science. 303(2004) 1831

  5. … and in industry • CO2reductioninvolved in • MeOHsynthesis • Urea synthesis • Methane (tri-)reforming • Dimethylcarbonate production • …

  6. Catalytic carbon dioxide hydrogenation for organic synthesis MeOH (a chemical & an energy vector) Industrial catalyst: Cu/ZnO/Al2O3 50-100 bar 500-550 K CO + CO2+3H2 CH3OH + H2O + CO ??! T. Kim, et al. J. Micromech. Microeng. 16 (2006) 1760

  7. Modeling to understand… CO2hydrogenationto MeOH Cu(100) ptot=1.5 bar T = 543 K no difference with/without CO in the stream Ni/Cu(100) a) pCO+CO2+H2=100+30+1370 mbar b) pCO+CO2+H2=0+30+1470 mbar T = 543 K … and now CO makes the difference ! J. Nerlov, I. ChorkendorffJ. Catal. 181 (1999) 271

  8. In ourexample: CO2hydrogenationto MeOH • Using Ni/Cu alloys: • CO2turnover frequency is notably higher at Ni sites with respect to Cu sites • Formate is observed as stable intermediate in situ • MeOH carbon and oxygen atoms come from CO2, but CO is needed

  9. ... WHAT IS HAPPENING THERE ??? ... … willthis talk be aboutsurfacescience? …may the latterhaveanything to do with «real» catalysis?

  10. Thisishow Chemistsseeit… Surface Science Pressure Gap Material Gap

  11. Surface Science Pressure Gap Material Gap Thisishow Physicistsseeit…

  12. Going on with our sample reaction… ... let’sdig up atomiclevelinsight … 1.under model UHV conditions…

  13. What is known about Cu (DFT): A.A. Gokhale, J.A. Dumesic, M. Mavrikakis, J ACS130 (2008) 1402

  14. And Whatabout Ni ?

  15. CO2 adsorption on Ni(110) - UHV • chemisorption states • e-injection -> CO2 bends • activatedchemisorbed state Thereis a stable CO2species  «seen»for the first time (16x22 Å2) PRB76 (2007) 195425, PRB 82 (2010) 165403; H-J. Freund, M. Roberts Surf. Sci.Rep.25 (1996) 225.

  16. DFT CO2reduction on Ni(110) – UHV+DFT H+CO2 coadsorption: Formate – similar to Cu at high pressure Hgas+CO2 JACS 130 (2008) 11417, JPCL 1 (2010) 402

  17. Whatwegot up to hereabout Ni: • Ni activates CO2 for reduction • There are twoparallelpathways • Formate (spectator, slow conversion rate) • Hydrocarboxyl intermediate (fast reaction) • AND WHAT ABOUT • Ni doping/alloying • The role of CO

  18. Tailoring bimetallic alloy surface properties: i) self-diffusion processes Ni/Cu(110) Segregation is determined by kinetics ! Synchrotron radiation time-resolved X-ray photoelectron spectroscopy JACS 134 (2012) 16827

  19. Tailoring bimetallic alloy surface properties: ii) molecule-metal interaction CO/CO2/Ni/Cu(110) Tuning the CO2 dissociation barrier… … and the adsorption energies. ACS Catal. 3 (2013) 1555

  20. So in Ni/Cu alloysthereis a delicate interplaybetween energetics and kinetics in the Ni/Cu segregationprocess + adsorbate binding, and decomposition !

  21. Can we therefore steer the chemistry of carbon oxides on a NiCu Catalyst by controlling Ni concentration? ACS Catal. 3 (2013) 1555

  22. In the case of our model reaction… CO/CO2/Ni/Cu(110) - UHV This is here, and not there! ACS Catal. 3 (2013) 1555

  23. We can also indirectly control the local adsorption sites of CO CO/CO2/Ni/Cu(110) - UHV CO adsorption metal: from Cu to Ni as a function of T Binding energy CO adsorption site on Ni: top vs bridge In preparation.

  24. Summarizing about Ni alloying…. • We can influence • CO and CO2 bindingenergies • CO adsorptionsites • Reactionbarriers

  25. 2.Bridging material gaps…

  26. Beyond the material Gap Cu@AlxOy/Ni3Al(111) Schmid et al. PRL 99 (2007) 196104, Becker et al. NewJPhys4 (2002) 75.

  27. CO/Cu@AlxOy/Ni3Al(111): modeling the Boudouard reaction… 2COCO2+C CO CO CO C C C In preparation.

  28. Cluster sizeeffect The smaller the cluster, the more efficient the conversion In preparation.

  29. CO/Cu@AlxOy/Ni3Al(111) Boudouard reaction: itgoesEley-Rideal In preparation.

  30. 3.Bridging pressure gap…

  31. NAP-XPS at Bessy CO+CO2+H2/Ni(110) @ 0.3 mbar You end up with carbide and graphene You end up with oxide JPCL (2014) DOI: 10.1021/jz5007675.

  32. The role of graphene and oxide CO+CO2+H2/Ni(110) @ 0.3 mbar Ni oxide carbide graphene Active surface for MeOHsynthesis…. JPCL (2014) DOI: 10.1021/jz5007675.

  33. The role of graphene and oxide CO+CO2+H2/Ni(110) @ 0.3 mbar CO removesNiO H2removes carbon  Metallic Ni  activephase JPCL (2014) DOI: 10.1021/jz5007675.

  34. Finally we got some hints about the role of CO • CO influencessegregationat the surface of Ni/Cu alloys • CO yieldscarbide/graphene by Eley-Rideal mechanisms (Boudouard reaction) • CO removesoxygen from Ni, whichishardlyremoved by hydrogen, yieldingmetallic, active Ni • CO and CO2 adsorptionsites, bindingenergies, and reactionbarriers can be tuned by means of Ni doping • Wehaveevidenced finite size, support, and coverageeffects

  35. 4.Totally bridging the pressure gap…

  36. Sum Frequency Generation VibrationalSpectroscopy Non-linear opticaltechniqueintrinsicallyselective for interfaces

  37. Vis-IR SFG Spectroscopy Lab @ UniTs

  38. Notonlyvibrations, butalsoelectronicconfiguration: the case of CO/Ni(110)

  39. Notonlyvibrations, butalsoelectronicconfiguration: the case of CO/Ni(110) CO+C/Ni φ = 345° CO/Ni φ = 310° Ni carbide Unpublished.

  40. 5.Towards in situ electrochemistry…

  41. Stability of Cu-PC/C cathode for CO2 electroreduction Cu-Pc basedcathodes Anodicalcoholoxidationinstead of water oxidation -40% energyconsumption Energy Technology (2014) DOI 10.1002/ente.201402014.

  42. And in situ electrochemistry…. close to come in our lab…

  43. Conclusions - UHV • Cu doesnotactivate CO2 • Ni activates CO2 via e- transfer • Formate is a spectatorratherthan a reaction intermediate on Ni • Hydrocarboxyl intermediatesmay play a determiningrole in CO2 conversion on Ni • Ni/Cu alloys show peculiar CO2 reductionactivity due to the interplaybetweendiffusion and segregationeffects • Surface Ni concentration can be used to taylor the alloyreactivity and the equilibriumbetween CO2 and CO adsorptionenergies

  44. Conclusions – beyond the pressure gap • The delicate interplaybetween graphene, carbide, and oxidephases on Ni can be governedusing CO in the gas stream in order to yield an activesurfacephase

  45. Conclusions – beyond the material gap • Finite size and coverageeffectsmay open unexpectedreactionchannelslike, in the case of CO, decomposition and carbideaccumulationat Cu clusters

  46. Conclusions –going liquid… • Will come soon !!

  47. THANK YOU ! • FUNDING • Financial support was obtained from • Italian MIUR (FIRB 2010 project RBFR10J4H7) • Fondazione Kathleen Foreman Casali • BeneficentiaStiftung • Consorzio per la Fisica – Trieste • UniTs – FRA 2012 • Italian Ministry of Foreign Affairs PEOPLE Africh C, Bevilacqua M, Baldereschi A, Bozzini B, Comelli G, De Rogatis L, Dri C, Filippi J, Fornasiero P, Greiner M, Knop-Gericke A, Miller H, Lacovig P, OlmosAsar J, Peressi M, Peronio A, Rizzi M, Rocca M, Savio L, Schlögl R, Vattuone L. OlmosAsar J, Peressi M

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